They are.

Tjue (twenty) finish by en "open mouth" french "A" sounds like [chuA] Sju (seven) sounds like more [chu] without "A" at the end. I'm french, this is my only way of distinguish each other :)

We also have tyve and syv. That is really fun. Though where I'm from, we mostly use tjue and syv. Well, I do at least :P

Rbsnh, if you find this difficult you can forget them and use tyve and syv. You say en-og-tyve (in one word), to-og-tyve etc.